Narrative:

Initially we were cleared direct per direct tul. We next received a pilot's discretion clearance to FL240 (we were currently at FL330). A few mins later ZKC gave us a clearance to turn 10 degrees to right for traffic (I then went from LNAV to heading select). About 20 seconds later, center changed his mind and told us to turn left and go direct tulsa (to do this I went back to the FMC and did a direct intercept to tul VOR). Center also said that he was 'going to take us over the top.' this did not register to either myself or the captain that he meant for us to maintain FL330 and to delete the pilot's discretion clearance to FL240. If ZKC actually said, 'maintain FL330' or terminology as appropriate, to cancel our pilot's discretion clearance to FL240, the captain and I did not recall hearing it or reading it back with our radio reply. When we started our descent from FL330, center called us and said that we were not cleared out of FL330. At the time we were about at FL290. Center then said to continue our descent and gave us the traffic advisory of 9:00 and 9 mi. (This occurred about 85 mi west of tulsa VOR on the 291 degree right.) if the captain and I did miss an appropriate radio call by ZKC to maintain FL330, there were 2 contributing factors: 1) I was busy reprogramming the FMC and may have not heard him give us the clearance to maintain FL330. 2) since we don't recall reading back, 'maintain FL330,' center should have queried us, as to our understanding of the clearance. Lesson learned: whenever there appears to be confusion by the controling agency, always make sure to get a full clearance from center, then read it back and make sure they 'roger' your readback. Another lesson learned: always report to ATC when vacating any previously assigned altitude/flight level for a newly assigned altitude/flight level.

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Original NASA ASRS Text

Title: AFTER SOME CONFUSION THE REPORTER FLT BEGAN A DESCENT FROM CRUISE ONLY TO BE TOLD BY ATC THAT THEIR DESCENT CLRNC HAD BEEN CANCELLED.

Narrative: INITIALLY WE WERE CLRED DIRECT PER DIRECT TUL. WE NEXT RECEIVED A PLT'S DISCRETION CLRNC TO FL240 (WE WERE CURRENTLY AT FL330). A FEW MINS LATER ZKC GAVE US A CLRNC TO TURN 10 DEGS TO RIGHT FOR TFC (I THEN WENT FROM LNAV TO HDG SELECT). ABOUT 20 SECS LATER, CENTER CHANGED HIS MIND AND TOLD US TO TURN LEFT AND GO DIRECT TULSA (TO DO THIS I WENT BACK TO THE FMC AND DID A DIRECT INTERCEPT TO TUL VOR). CENTER ALSO SAID THAT HE WAS 'GOING TO TAKE US OVER THE TOP.' THIS DID NOT REGISTER TO EITHER MYSELF OR THE CAPT THAT HE MEANT FOR US TO MAINTAIN FL330 AND TO DELETE THE PLT'S DISCRETION CLRNC TO FL240. IF ZKC ACTUALLY SAID, 'MAINTAIN FL330' OR TERMINOLOGY AS APPROPRIATE, TO CANCEL OUR PLT'S DISCRETION CLRNC TO FL240, THE CAPT AND I DID NOT RECALL HEARING IT OR READING IT BACK WITH OUR RADIO REPLY. WHEN WE STARTED OUR DSCNT FROM FL330, CENTER CALLED US AND SAID THAT WE WERE NOT CLRED OUT OF FL330. AT THE TIME WE WERE ABOUT AT FL290. CENTER THEN SAID TO CONTINUE OUR DSCNT AND GAVE US THE TFC ADVISORY OF 9:00 AND 9 MI. (THIS OCCURRED ABOUT 85 MI W OF TULSA VOR ON THE 291 DEG R.) IF THE CAPT AND I DID MISS AN APPROPRIATE RADIO CALL BY ZKC TO MAINTAIN FL330, THERE WERE 2 CONTRIBUTING FACTORS: 1) I WAS BUSY REPROGRAMMING THE FMC AND MAY HAVE NOT HEARD HIM GIVE US THE CLRNC TO MAINTAIN FL330. 2) SINCE WE DON'T RECALL READING BACK, 'MAINTAIN FL330,' CENTER SHOULD HAVE QUERIED US, AS TO OUR UNDERSTANDING OF THE CLRNC. LESSON LEARNED: WHENEVER THERE APPEARS TO BE CONFUSION BY THE CTLING AGENCY, ALWAYS MAKE SURE TO GET A FULL CLRNC FROM CENTER, THEN READ IT BACK AND MAKE SURE THEY 'ROGER' YOUR READBACK. ANOTHER LESSON LEARNED: ALWAYS RPT TO ATC WHEN VACATING ANY PREVIOUSLY ASSIGNED ALT/FLT LEVEL FOR A NEWLY ASSIGNED ALT/FLT LEVEL.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.